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A model for molecular weights in vinyl acetate emulsion polymerization
Author(s) -
Lee Chan H.,
Mallinson Richard G.
Publication year - 1988
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690340514
Subject(s) - vinyl acetate , dispersity , emulsion polymerization , chain transfer , polymerization , polymer chemistry , kinetic chain length , chemistry , radical polymerization , polymer , monomer , emulsion , chemical engineering , organic chemistry , copolymer , engineering
The continuous stirred tank emulsion polymerization of vinyl acetate has shown oscillatory behavior in conversion, particle size, molecular weight, and polydispersity during polymerization. The kinetics in vinyl acetate emulsion polymerization are especially complex because of chain transfer to polymer and monomer and the terminal double bond reaction. A nonsteady‐state model to predict the average molecular weights is developed for this polymerization system. Improved results are achieved by inclusion of the effects of polymer chain initiation and termination by absorbed radicals. It is found that the observed oscillations are closely related to the radical diffusion and desorption rates that are involved in a heterogeneous initiation mechanism. The molecular weights and polydispersities are successfully predicted by the model. The nature of the oscillations in these properties is examined.